The present invention relates to an apparatus and a method for carrying out a test to detect particles in urine, especially for carrying out a test to determine the susceptibility of a test subject to kidney stones whereby urine is taken from the test subjects and collected and the detection test is carried out whereby the urine after a stand time is poured out of the test vessel and residues of particles which may be present in the test vessel are subjected to an optical recognition, especially by treating them with a detection reagent, especially a dye reagent.
Such a kidney stone test is known from EP 0 889 326 which also proposes a modular system for carrying out the kidney stone test. In order to test the urine characteristics of a patient with respect to the susceptibility to kidney stones, the urine is checked as to whether calcium rich salts or particles precipitate. It is known to carry out the following significant steps in succession:
pouring 40 ml of directly obtained urine from a test subject into a petri dish or into a dish disposed centrally of a petri dish which contains a reaction substrate;
allowing a stand time (6 to 24 hours) to precipitate calcium particles;
discharging the petri dish contents and then washing with distilled water;
adding 400 xcexcl of a dilute aqueous HCl solution to the reaction substrate;
adding 150 xcexcl of an aqueous sodium acetate solution (5%, w/v) and adding 150 xcexcl of the indicator solution Arsenazo III (0.1%, w/v and mixing for 15 seconds;
then optically obtaining the test results in the form of a pink coloration of the solution in the case of a nonsusceptible test subject or a blue coloration of the solution in the case of a susceptible test subject whereby the blue coloration can have a shading from violet to blue. At the boundary region between a positive and negative result, the solution has a pink coloration with a slight bluish tint.
It is important that the test be carried out with freshly obtained and thus still warm urine to avoid possible falsification of test results by premature precipitation because of cooling down.
The assembly for carrying out the test has a petri dish with a cover together with a smaller central dish for receiving the reaction substrate and the required reagent.
This method or system has the following drawbacks:
Since the urine must be added to the petri dish while warm, a separate collection container is required for transferring the urine. Since the test should also be capable of being used as a preliminary test by the test subject at home, the test subject optionally must be provided with a written advisory to the effect that the urine must be collected in a separate container and directly added to the petri dish while warm. In addition, the test subject or user must add a definite quantity of the urine, namely, exactly 40 ml to the petri dish which makes a prior measurement of the urine quantity necessary. While the petri dish has a cover in the known system, possible transport of the petri dish is exceptionally difficulty and impractical especially for older people.
The known method of detecting positive or negative kidney stone suspicions requires a number of operative steps like washing and supplying a number of reagents and the use of exact quantities of liquids which are added as well as the observation of time constraints for handling, like for example agitation. The reagent Arsenazo III is also toxic and creates disposal problems for the user.
The test results are determined by the color of the solution and precisely in the boundary region (pink coloration with weak bluish tint) between a clearly positive or negative result is difficult to recognize which is affected by the fact that the positive result is a blue coloration ranging from the violet to the blue.
It is the object of the invention to provide an improved apparatus for carrying out a test for detecting particles in urine.
It is also an object of the invention to provide an improved method for carrying out such a test whereby these drawbacks are avoided.
Another object of the invention is to eliminate drawbacks of prior art methods of detecting susceptibility of a human patient or subject to kidney stones.
From an apparatus point of view, the object is achieved in that the apparatus has a collecting vessel in which the urine of the test subject can be directly collected and which simultaneously is also the test vessel. Thus the test vessel is column shaped or tubular, tapers toward the bottom and extends upwardly into an overflow region, preferably formed in one piece on the test vessel which preferably has a setpoint level mark for the required filling state for the orientation of the test subject. In addition, the apparatus has a closure element which plugs into the collecting vessel or the overflow region and expels any excess urine which may have collected into the overflow region in order to establish a defined quantity of the test urine in the test vessel and close the latter. Preferably the device has means forming a stand for the automatic positioning of the collecting vessel with a vertical orientation during the stand time.
From the method view point, the object is achieved in that the following steps are carried out for a urine test according to the invention:
collecting the urine from the test subject directly in a collecting vessel which serves simultaneously also as the test vessel where the test vessel is preferably column shaped and tapered toward the bottom and has an overflow region into which the column transitions upwardly whereby the test subject can optionally be oriented by a marking on the overflow region showing the full state or by collecting the urine in a collecting vessel whose contents are transferred into a test vessel;
preferably allowing excess above the volume of the test vessel of the collected urine to run off into the overflow region;
closing the collecting container preferably with a closure element and expressing the excess urine which may be present in the overflow region to establish a defined quantity of test urine in the test vessel or closing the test vessel,
waiting a predetermined stand time;
pouring off urine from the collecting container or the test vessel;
adding a detection reagent to the test vessel, especially in the convergingly shaped lower part of the test vessel. When required a strong acid, like HCl, can be added before the dye reagent is added.
The proposed apparatus for carrying out the test and the method has the following advantages and enables the following preferred further developments:
the test subject or the patient can collect the urine directly in the test vessel. It thus is insured that the urine, as is absolutely necessary for the test, is collected warm in the vessel and is not cooled by otherwise required handling as, for example, transfer.
The amount of urine required for the test is insured by the fact that the test subject can be oriented on the one hand by the level marking and on the other hand by the overflow region and the closure element which has a liquid displacement effect guaranteeing the correct test quantity so that after an ordinary closure within the test vessel, the required amount of urine is present. That means that the closure element, which preferably can be a screw closure, engages in the preferably funnel shaped overflow region and seals the test vessel with a defined volume at the end of the screw tightening process.
The test vesselxe2x80x94as the lower part of the collecting vesselxe2x80x94is column shaped or tube shaped according to the invention and has its bottom convergingly shaped or tapered and thus has a plug shape. This insures that the particles precipitating from the saturated urine solution will be concentrated at a limited location upon settling.
As the detection reagent, a dye reagent is selected which is neither toxic nor poisonous, for example, from the group of calcium indicators.
Such dye reagents have the advantage that they enable a clearer indication of the test results than the dye reagent of EP 0 889 326, in that the colors are clearly differentiable. Thus negative results are indicated by a strawberry red color or gray while positive results are indicated by a dark red or green.
To facilitate the reading of the results by the user with the aid of different dyes, the tapered bottom of the column shaped test vessel can additionally have a cuvette-like extension in which the dye reagent can preferably be added. The aforedescribed geometry enables good optical discrimination of different color results.